WPF datagrid头文本绑定

Question

由于某种原因,DataGrid的列标题不是FrameWork元素,因此您不能使用绑定来设置标题文本之类的内容.如果用.NET 4.0改变了(如果我现在使用的是CodePlex的最新WPFToolkit),请纠正我.

我正在尝试使用DataGrid进行时间表演示,其中日期应该是标题文本的一部分(即"Sun,Nov 01"),我在XAML中有以下内容:

        <dg:DataGrid.Columns>
        <dg:DataGridTextColumn Header="Description" Width="Auto" Binding="{Binding Description}" IsReadOnly="True"/>
        <dg:DataGridTextColumn Header="Mon" Width="50" Binding="{Binding Allocations[0].Amount}"  />
... every other day of the week ....
        <dg:DataGridTextColumn Header="Sun" Width="50" Binding="{Binding Allocations[6].Amount}"  />
        <dg:DataGridTextColumn Header="Total" MinWidth="50" Binding="{Binding TotalAllocatedAmount}" IsReadOnly="True" />
    </dg:DataGrid.Columns>

我想使用我用于数据的相同AllocationViewModel(即"{Binding Allocations [0] .Amount}"并将它的DisplayName属性绑定到标题文本.有人可以告诉我该怎么做吗？如果我有要使用静态资源,我如何在那里获取DataContext？

编辑----------------优先工作 - 周围

Josh Smith在一段时间后发布了一篇关于DataContextSpy的文章,这是我遇到这个问题时最干净的解决方法.这是让它工作的类:

/// <summary>
/// Workaround to enable <see cref="DataContext"/> bindings in situations where the DataContext is not redily available. 
/// </summary>
/// <remarks>http://blogs.infragistics.com/blogs/josh_smith/archive/2008/06/26/data-binding-the-isvisible-property-of-contextualtabgroup.aspx</remarks>
public class DataContextSpy : Freezable
{
    public DataContextSpy()
    {
        // This binding allows the spy to inherit a DataContext.
        BindingOperations.SetBinding(this, DataContextProperty, new Binding());
    }

    public object DataContext
    {
        get { return GetValue(DataContextProperty); }
        set { SetValue(DataContextProperty, value); }
    }

    // Borrow the DataContext dependency property from FrameworkElement.
    public static readonly DependencyProperty DataContextProperty = FrameworkElement
        .DataContextProperty.AddOwner(typeof (DataContextSpy));

    protected override Freezable CreateInstanceCore()
    {
        // We are required to override this abstract method.
        throw new NotImplementedException();
    }
}

有了这个,我可以在xaml中劫持我需要的DC:

    <dg:DataGrid.Resources>
        <behavior:DataContextSpy x:Key="spy" DataContext="{Binding Allocations}" />
    </dg:DataGrid.Resources>

然后根据需要通过绑定应用:

            <dg:DataGridTextColumn Header="{Binding Source={StaticResource spy}, Path=DataContext[0].DisplayName}" 
                               Width="50" Binding="{Binding Allocations[0].Amount}"  />

徐-weet!

Answer 1

这是将DataGridTextColumn标头绑定到数据上下文的简单方法:

<DataGrid x:Name="summaryGrid" Grid.Row="3" AutoGenerateColumns="False" IsReadOnly="True" CanUserAddRows="False">
       <DataGrid.Columns>
            <DataGridTextColumn Header="Hard Coded Title" Width="*"/>
            <DataGridTextColumn Width="100">
                <DataGridTextColumn.Header>
                    <TextBlock Text="{Binding DataContext.SecondColumnTitle, 
                                              RelativeSource={RelativeSource AncestorType={x:Type local:MainWindow}}}"/>
                </DataGridTextColumn.Header>
            </DataGridTextColumn>
            <DataGridTextColumn Width="150">
                <DataGridTextColumn.Header>
                    <TextBlock Text="{Binding DataContext.ThirdColumnTitle, 
                                              RelativeSource={RelativeSource AncestorType={x:Type local:MainWindow}}}"/>
                </DataGridTextColumn.Header>
            </DataGridTextColumn>
        </DataGrid.Columns>
    </DataGrid>

您显然需要具有属性:SecondColumnTitle并ThirdColumnTitle在您的数据上下文类中实现.

我有这个解决方案在.net 4.5中工作,并没有机会也没有理由在早期版本的框架中尝试它.

Answer 2

我的解决方案允许在DataGridColumn需要绑定的属性名称中写入一行。他有以下特点：

• 有支持 DataGridTextColumn
• 有支持 DataGridTemplateColumn
• StringFormat为每一列设置
• 指定静态值 StringFormat
• 完全符合MVVM模式

下面的示例包括StringFormat（他应该站在 之前PropertyPath）：

<DataGridTextColumn Behaviors:DataGridHeader.StringFormat="StringFormat: {0:C}"
                    Behaviors:DataGridHeader.PropertyPath="HeaderValueOne" ... /> 

相当于一条这条线：

<DataGridTextColumn HeaderStringFormat="{0:C}"
                    Header="{Binding Path=HeaderValueOne}" ... />

谁需要更多解决方案和功能的示例，请阅读以下内容。

Link 对于示例项目。

Notes about the solution

从我之前看到的所有解决方案中，对我来说最简单的解决方案是这样的example：

<DataGridTextColumn Binding="{Binding Name}">
    <DataGridTextColumn.HeaderTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding Path=DataContext.YourPropertyName,
                                      RelativeSource={RelativeSource AncestorType={x:Type SomeControl}}" />
         </DataTemplate>
    </DataGridTextColumn.HeaderTemplate>
</DataGridTextColumn>        

请注意DataGridTextColumn.HeaderTemplate，如果使用了DataGridTextColumn.Header，那么对于 .NET 框架低于 4.5 版本和 Silverlight 会产生异常：

Header 属性不支持 UIElements

似乎有什么必要？我想找到一个解决方案，允许在DataGridColumn需要绑定的属性名称中写入一行。

这就是发生的事情：

<DataGridTextColumn Behaviors:DataGridHeader.PropertyPath="HeaderValueOne" // Attached dependency property 

这种结构类似于：

<DataGridTextColumn Header="{Binding Path=HeaderValueOne}" ... />

也可以StringFormat像这样用于每一列：

<DataGridTextColumn Behaviors:DataGridHeader.StringFormat="StringFormat: {0:C}"
                    Behaviors:DataGridHeader.PropertyPath="TestStringFormatValue" ... />

并且可以为 指定静态值StringFormat：

<DataGridTextColumn Behaviors:DataGridHeader.StringFormat="{x:Static Member=this:TestData.TestStaticStringFormatValue}" // public static string TestStaticStringFormatValue = "Static StringFormat: {0}$";
                    Behaviors:DataGridHeader.PropertyPath="TestStringFormatValue"

这是原始的DataTemplate，它被动态设置为列：

<DataTemplate>
    <TextBlock Text="{Binding Path=DataContext.YourPropertyName,
                              StringFormat="YourStringFormat",
                              RelativeSource={RelativeSource AncestorType={x:Type DataGridCellsPanel}}}" />
</DataTemplate>

为了RelativeSource不依赖的类型DataContext，我solution从先生那里得到了很大的帮助Bruno。

在这种情况下，DataGridCellsPanel包含为父 DataGrid 设置的正确 DataContext。

以下是执行所有魔术的基本代码：

IsSetHeader PropertyChanged handler

private static void IsSetHeader(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
    var textColumn = sender as DataGridTextColumn;
    var templateColumn = sender as DataGridTemplateColumn;
    string path = e.NewValue as string;

    if ((textColumn == null) & (templateColumn == null)) 
    {
        return;
    }

    if (String.IsNullOrEmpty(path) == false)
    {
        currentStringFormat = ReturnStringFormat(textColumn, templateColumn);
        dataTemplate = CreateDynamicDataTemplate(path, currentStringFormat);

        if (dataTemplate != null)
        {
            if (textColumn != null)
                textColumn.HeaderTemplate = dataTemplate;

            if (templateColumn != null)
                templateColumn.HeaderTemplate = dataTemplate;
        }
    }
}

CreateDynamicDataTemplate

private static DataTemplate CreateDynamicDataTemplate(string propertyPath, string stringFormat)
{
    var pc = new ParserContext();
    MemoryStream sr = null;

    string xaml = GetXamlString(propertyPath, stringFormat);            
    sr = new MemoryStream(Encoding.ASCII.GetBytes(xaml));

    pc.XmlnsDictionary.Add("", "http://schemas.microsoft.com/winfx/2006/xaml/presentation");
    pc.XmlnsDictionary.Add("x", "http://schemas.microsoft.com/winfx/2006/xaml");

    return XamlReader.Load(sr, pc) as DataTemplate;
}

GetXamlString

private static string GetXamlString(string propertyPath, string stringFormat)
{
    #region Original PropertyPath for TextBlock

    // {Binding Path=DataContext.YourProperty, RelativeSource={RelativeSource AncestorType={x:Type DataGridCellsPanel}}}"
    // Thanks to Bruno (/sf/users/17368291/) for this trick

    #endregion

    var sb = new StringBuilder();

    sb.Append("<DataTemplate><TextBlock Text=\"{Binding Path=DataContext.");
    sb.Append(propertyPath);
    sb.Append(", StringFormat=");
    sb.Append(stringFormat);
    sb.Append(", RelativeSource={RelativeSource AncestorType={x:Type DataGridCellsPanel}}}\" /></DataTemplate>");

    return sb.ToString();
}

StringFormat必须出现在 PropertyPath 之前，因为它是可选的。为了对于列，没有它的人不会发生异常，我注册了 try-catch GetStringFormat：

 public static string GetStringFormat(DependencyObject DepObject)
 {
    try
    {
        return (string)DepObject.GetValue(StringFormatProperty);
    }

    catch 
    {
        return String.Empty;
    }
 }

另外：不要在尝试获取值的方法 try-catch 块中写入。

减号：StringFormat程序启动时，将为每个错过的异常生成一次减号。如果它对您很重要，您始终可以StringFormat="null"为列指定。

以防万一，显示项目的完整代码：

public static class DataGridHeader
{
    #region Private Section

    private static string textColumnStringFormat = null;
    private static string templateColumnStringFormat = null;
    private static string currentStringFormat = null;
    private static DataTemplate dataTemplate = null;

    #endregion

    #region PropertyPath DependencyProperty

    public static readonly DependencyProperty PropertyPathProperty;

    public static void SetPropertyPath(DependencyObject DepObject, string value)
    {
        DepObject.SetValue(PropertyPathProperty, value);
    }

    public static string GetPropertyPath(DependencyObject DepObject)
    {
        return (string)DepObject.GetValue(PropertyPathProperty);
    }

    #endregion

    #region StringFormat DependencyProperty

    public static readonly DependencyProperty StringFormatProperty;

    public static void SetStringFormat(DependencyObject DepObject, string value)
    {
        DepObject.SetValue(StringFormatProperty, value);
    }

    public static string GetStringFormat(DependencyObject DepObject)
    {
        try
        {
            return (string)DepObject.GetValue(StringFormatProperty);
        }

        catch 
        {
            return String.Empty;
        }
    }

    #endregion

    #region Constructor

    static DataGridHeader()
    {
        PropertyPathProperty = DependencyProperty.RegisterAttached("PropertyPath",
                                                                   typeof(string),
                                                                   typeof(DataGridHeader),
                                                                   new UIPropertyMetadata(String.Empty, IsSetHeader));

        StringFormatProperty = DependencyProperty.RegisterAttached("StringFormat",
                                                                   typeof(string),
                                                                   typeof(DataGridHeader),
                                                                   new UIPropertyMetadata(String.Empty));  
    }

    #endregion

    #region IsSetHeader PropertyChanged Handler

    private static void IsSetHeader(DependencyObject sender, DependencyPropertyChangedEventArgs e)
    {
        var textColumn = sender as DataGridTextColumn;
        var templateColumn = sender as DataGridTemplateColumn;
        string path = e.NewValue as string;

        if ((textColumn == null) & (templateColumn == null)) 
        {
            return;
        }

        if (String.IsNullOrEmpty(path) == false)
        {
            currentStringFormat = ReturnStringFormat(textColumn, templateColumn);
            dataTemplate = CreateDynamicDataTemplate(path, currentStringFormat);

            if (dataTemplate != null)
            {
                if (textColumn != null)
                    textColumn.HeaderTemplate = dataTemplate;

                if (templateColumn != null)
                    templateColumn.HeaderTemplate = dataTemplate;
            }
        }
    }

    #endregion

    #region ReturnStringFormat Helper

    private static string ReturnStringFormat(DependencyObject depObject1, DependencyObject depObject2) 
    {
        textColumnStringFormat = GetStringFormat(depObject1) as string;
        templateColumnStringFormat = GetStringFormat(depObject2) as string;

        if (String.IsNullOrEmpty(textColumnStringFormat) == false)
        {
            return textColumnStringFormat;
        }

        if (String.IsNullOrEmpty(templateColumnStringFormat) == false)
        {
            return templateColumnStringFormat;
        }

        return "null";
    }

    #endregion

    #region CreateDynamicDataTemplate Helper

    private static DataTemplate CreateDynamicDataTemplate(string propertyPath, string stringFormat)
    {
        var pc = new ParserContext();
        MemoryStream sr = null;

        string xaml = GetXamlString(propertyPath, stringFormat);            
        sr = new MemoryStream(Encoding.ASCII.GetBytes(xaml));

        pc.XmlnsDictionary.Add("", "http://schemas.microsoft.com/winfx/2006/xaml/presentation");
        pc.XmlnsDictionary.Add("x", "http://schemas.microsoft.com/winfx/2006/xaml");

        return XamlReader.Load(sr, pc) as DataTemplate;
    }

    #endregion

    #region GetXamlString Helper

    private static string GetXamlString(string propertyPath, string stringFormat)
    {
        #region Original PropertyPath for TextBlock

        // {Binding Path=DataContext.YourProperty, RelativeSource={RelativeSource AncestorType={x:Type DataGridCellsPanel}}}"
        // Thanks to Bruno (/sf/users/17368291/) for this trick

        #endregion

        var sb = new StringBuilder();

        sb.Append("<DataTemplate><TextBlock Text=\"{Binding Path=DataContext.");
        sb.Append(propertyPath);
        sb.Append(", StringFormat=");
        sb.Append(stringFormat);
        sb.Append(", RelativeSource={RelativeSource AncestorType={x:Type DataGridCellsPanel}}}\" /></DataTemplate>");

        return sb.ToString();
    }

    #endregion
}

XAML

<Window x:Class="BindingHeaderInDataGrid.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:this="clr-namespace:BindingHeaderInDataGrid"
        xmlns:Behaviors="clr-namespace:BindingHeaderInDataGrid.AttachedBehaviors"
        WindowStartupLocation="CenterScreen"
        Title="MainWindow" Height="220" Width="600">

    <Window.DataContext>
        <this:TestData />
    </Window.DataContext>

    <Grid Name="TestGrid">
        <DataGrid Name="TestDataGrid" 
                  Width="550"
                  Height="100"
                  Margin="10"
                  VerticalAlignment="Top"
                  Background="AliceBlue">

            <DataGrid.Columns>
                <DataGridTextColumn Behaviors:DataGridHeader.StringFormat="StringFormat: {0:C}"
                                    Behaviors:DataGridHeader.PropertyPath="TestStringFormatValue"
                                    Width="100"
                                    IsReadOnly="False">

                    <DataGridTextColumn.HeaderStyle>
                        <Style TargetType="{x:Type DataGridColumnHeader}">
                            <Setter Property="Height" Value="20" />
                            <Setter Property="Background" Value="Pink" />
                            <Setter Property="Margin" Value="2,0,0,0" />
                        </Style>
                    </DataGridTextColumn.HeaderStyle>
                </DataGridTextColumn>

                <DataGridTextColumn Behaviors:DataGridHeader.StringFormat="{x:Static Member=this:TestData.TestStaticStringFormatValue}"
                                    Behaviors:DataGridHeader.PropertyPath="TestStringFormatValue"
                                    Width="2*"
                                    IsReadOnly="False">

                    <DataGridTextColumn.HeaderStyle>
                        <Style TargetType="{x:Type DataGridColumnHeader}">
                            <Setter Property="Height" Value="20" />
                            <Setter Property="Background" Value="CadetBlue" />
                            <Setter Property="Margin" Value="2,0,0,0" />
                        </Style>
                    </DataGridTextColumn.HeaderStyle>
                </DataGridTextColumn>

                <DataGridTextColumn Behaviors:DataGridHeader.PropertyPath="TestUsualHeaderValue"
                                    Width="1.5*" 
                                    IsReadOnly="False">

                    <DataGridTextColumn.HeaderStyle>
                        <Style TargetType="{x:Type DataGridColumnHeader}">
                            <Setter Property="Height" Value="20" />
                            <Setter Property="Background" Value="Gainsboro" />
                            <Setter Property="Margin" Value="2,0,0,0" />
                        </Style>
                    </DataGridTextColumn.HeaderStyle>
                </DataGridTextColumn>

                <DataGridTemplateColumn Behaviors:DataGridHeader.PropertyPath="TestTemplateColumnValue"
                                        Width="150"
                                        IsReadOnly="False">

                    <DataGridTemplateColumn.HeaderStyle>
                        <Style TargetType="{x:Type DataGridColumnHeader}">
                            <Setter Property="Height" Value="20" />
                            <Setter Property="Background" Value="Beige" />
                            <Setter Property="Margin" Value="2,0,0,0" />
                        </Style>
                    </DataGridTemplateColumn.HeaderStyle>
                </DataGridTemplateColumn>
            </DataGrid.Columns>
        </DataGrid>

        <Button Name="ChangeHeader" 
                Width="100" 
                Height="30"
                VerticalAlignment="Bottom"
                Content="ChangeHeader" 
                Click="ChangeHeader_Click" />
    </Grid>
</Window>

Code-behind

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }        

    private void ChangeHeader_Click(object sender, RoutedEventArgs e)
    {
        TestData data = this.DataContext as TestData;

        data.TestStringFormatValue = "777";
        data.TestUsualHeaderValue = "DynamicUsualHeader";
        data.TestTemplateColumnValue = "DynamicTemplateColumn";
    }
}

public class TestData : NotificationObject
{
    #region TestStringFormatValue

    private string _testStringFormatValue = "1";

    public string TestStringFormatValue
    {
        get
        {
            return _testStringFormatValue;
        }

        set
        {
            _testStringFormatValue = value;
            NotifyPropertyChanged("TestStringFormatValue");
        }
    }

    #endregion

    #region TestStaticStringFormatValue

    public static string TestStaticStringFormatValue = "Static StringFormat: {0}$";

    #endregion

    #region TestUsualHeaderValue

    private string _testUsualHeaderValue = "UsualHeader";

    public string TestUsualHeaderValue
    {
        get
        {
            return _testUsualHeaderValue;
        }

        set
        {
            _testUsualHeaderValue = value;
            NotifyPropertyChanged("TestUsualHeaderValue");
        }
    }

    #endregion

    #region TestTemplateColumnValue

    private string _testTemplateColumnValue = "TemplateColumn";

    public string TestTemplateColumnValue
    {
        get
        {
            return _testTemplateColumnValue;
        }

        set
        {
            _testTemplateColumnValue = value;
            NotifyPropertyChanged("TestTemplateColumnValue");
        }
    }

    #endregion
}

Answer 3

我知道这篇文章很旧，但是当我查找如何执行此操作时，这是第一个出现的条目。我不喜欢这个答案，因为它看起来有点矫枉过正。经过更多搜索，我找到了这个链接，该链接展示了如何使用模板列在标记中执行此操作。

<DataGridTemplateColumn>
    <DataGridTemplateColumn.HeaderTemplate>
        <DataTemplate>
            **<TextBlock Text="{Binding DataContext.HeaderTitle, RelativeSource={RelativeSource AncestorType={x:Type DataGrid}}}" />**
        </DataTemplate>
    </DataGridTemplateColumn.HeaderTemplate>
    <DataGridTemplateColumn.CellTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding}" Width="200" />
        </DataTemplate>
    </DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>

Answer 4

我通过使用HeaderTemplate和 绑定到DataContext的DataGrid，使用解决了这个问题RelativeSource。

<DataGrid ItemsSource="{Binding Items}">
    <DataGrid.Columns>
        <DataGridTextColumn Binding="{Binding Value1}">
            <DataGridTextColumn.HeaderTemplate>
                <DataTemplate>
                    <TextBlock Text="{Binding DataContext.ColumnTitel1, RelativeSource={RelativeSource AncestorType={x:Type DataGrid}}}"/>
                </DataTemplate>
            </DataGridTextColumn.HeaderTemplate>
        </DataGridTextColumn>
    </DataGrid.Columns>
</DataGrid>

Header属性内的相同绑定不起作用。

Answer 5

**编辑 ：-

您可以设置 DataGridColumnHeader 的样式并执行一些时髦的绑定。尝试在这里下载 ColumnHeaderBindings.zip，它有一个小测试项目，这有点黑客，但它有效

**编辑结束

列上的绑定发生在每行的基础上，该列不是可视化树的一部分，绑定应用于网格中的每个项目，从网格源代码中您可以看到属性 Binding 有这些注释

    /// <summary>
    ///     The binding that will be applied to the generated element.
    /// </summary>
    /// <remarks>
    ///     This isn't a DP because if it were getting the value would evaluate the binding.
    /// </remarks>

因此，绑定到列没有多大意义，因为正如您所发现的，当您不是可视化树的一部分时，您就没有数据上下文。

当您想要绑定到项目源时，ComboBoxColumn 也存在同样的问题。您可以绑定到 StaticResource，但 StaticResource 也没有数据上下文。您可以使用对象数据提供程序或直接在 xaml 中实例化。

但我只是在代码中创建列，并设置标题。那么这个问题就会消失。

这里有一篇关于视觉布局的好文章。